Mechanically Enhanced Biodrying of Biosolids Using the Agitated Bay Composting System

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Mechanically Enhanced Biodrying of Biosolids Using the Agitated Bay Composting System Lissa Ham Siemens Water Technologies Inc. Richard Nicoletti, PE Siemens Water Technologies Inc.

1 Mechanically Enhanced Biodrying of Biosolids Using the Agitated Bay Composting System Lissa Ham Siemens Water Technologies Inc. Richard Nicoletti, PE Siemens Water Technologies Inc. Lewis Naylor, PhD Apple Environmental Services James Taylor Town of Merrimack, New Hampshire 21 st Annual Conference - Compost Council of Canada September 2011 Charlottetown, P.E.I. Siemens AG, 2011 All rights reserved Page 1 Date Author filename.ppt Water Technologies

2 Biosolids Management Beneficial Reuse Changes Focus has shifted towards - Energy Recovery - Energy Generation Page 2 Date Author filename.ppt Water Technologies

3 Biosolids Management Challenges Changes in biosolids management practices and industry Woody amendment now a commodity Traditional drying consumes energy Outdoor drying poses issues Focus on using biosolids as energy source Page 3 Date Author filename.ppt Water Technologies

4 Biosolids Management Mechanically Enhanced Biodrying Latest application for the IPS agitated bed technology Page 4 Date Author filename.ppt Water Technologies

5 Biosolids Management Solution Controlled/automated agitation and aeration Biodried biosolids recycled as amendment Enclosed facility avoids weather impact Biodrying saves energy compared to traditional drying End product use as fuel or fertilizer Flexibility to biodry or fertilizer Page 5 Date Author filename.ppt Water Technologies

6 Biosolids Management Composting Drying Biodrying Technology Comparison Page 6 Date Author filename.ppt Water Technologies

7 Biosolids Management Composting vs. Biodrying Similarities Biological process Self generated heat Static/Mechanical 18 days Area depends on process Differences Cellulose Amendment vs. Dried Biosolids Moisture Control Sludge Volatile Solids critical Technology Comparison Page 7 Date Author filename.ppt Water Technologies

8 Biosolids Management Drying vs. Biodrying Similarities Stabilize /reduce moisture & volume Recycles dried biosolids Mechanical Produces fertilizer/fuel Differences Thermal vs biological process Supplied vs selfgenerated heat 24 hours vs 18 days Retains calorific value Space requirements Technology Comparison Page 8 Date Author filename.ppt Water Technologies

9 Biodrying Biodrying: Partially drying biological materials using self generated heat from microbial biochemical processes. Dry by air/sun - impacted by sun/ humidity/ temperature Subject to extreme weather Occasional manual turning Takes months to dry Page 9 Date Author filename.ppt Water Technologies

Solar Drying Discovery Bay WWTP Solar Dryer Discovery Bay, CA Parkson Thermo System Solar Sludge Dryer Solar drying: Low tech/low energy Water either evaporates or drains Requires

10 Solar Drying Discovery Bay WWTP Solar Dryer Discovery Bay, CA Parkson Thermo System Solar Sludge Dryer Solar drying: Low tech/low energy Water either evaporates or drains Requires space Potential alternate disposal method in wet/cold season or added energy Odor potential CAPEX/OPEX - Low /Moderate Class B end product Page 10 Date Author filename.ppt Water Technologies

Mechanically Enhanced Biodrying IPS Mechanically Enhanced Biodrying: Incorporates mechanical processes such as forced aeration and pile agitation to further expedite moisture

11 Mechanically Enhanced Biodrying IPS Mechanically Enhanced Biodrying: Incorporates mechanical processes such as forced aeration and pile agitation to further expedite moisture evaporation. Increases microbial activity Self-generated heat Automated process control and turning Fully enclosed Days to dry Page 11 Date Author filename.ppt Water Technologies

Mechanically Enhanced Biodrying MEB: Low energy needed Moisture evaporates Optimizes space Unaffected by extreme climate conditions Odors

12 Mechanically Enhanced Biodrying MEB: Low energy needed Moisture evaporates Optimizes space Unaffected by extreme climate conditions Odors contained/treated CAPEX/OPEX - Moderate Class A end product Flexibility compost or biodry Page 12 Date Author filename.ppt Water Technologies

Lewis Naylor, PhD Pilot Study Process Consultant and

13 Mechanically Enhanced Biodrying Mr. Richard Nicoletti, P.E. Pilot Study Project Manager Mr. Lewis Naylor, PhD Pilot Study Process Consultant and Evaluator Pilot Study Personnel Page 13 Date Author filename.ppt Water Technologies

Facility Merrimack, New Hampshire September 2009 February 2010 Pre- Pilot Test Pilot

14 Mechanically Enhanced Biodrying Anthony Dupont Compost Facility Bristol, Rhode Island Summer Trial July - August 2008 Phase I Phase II Merrimack Composting Facility Merrimack, New Hampshire September 2009 February 2010 Pre- Pilot Test Pilot Test Winter Trial Study Locations Page 14 Date Author filename.ppt Northeast USA Water Technologies

15 Mechanically Enhanced Biodrying Study Goals Warm weather trials, June- August 2008, Bristol, RI Test use of dried biosolids as single amendment Determine biodrying potential/time requirements Determine pathogen destruction capability Mechanical and biological limits of the IPS Technology Goals Page 15 Date Author filename.ppt Water Technologies

16 Mechanically Enhanced Biodrying Study Goals Cold Weather Trials, September 2009 February 2010, Merrimack, NH Test ability to achieve 65% solids at ambient temperatures < 0 C Assess production of adequate compost for recycle Confirm retention time in bay Evaluate pathogen destruction temperatures and PFRP temperatures Estimate heating value of product for fuel use Identify critical input/output parameters and boundary conditions Goals Page 16 Date Author filename.ppt Water Technologies

17 IPS System Overview MEB Process Flow Diagram Page 17 Date Author filename.ppt Water Technologies

18 IPS System Overview Agitated Bay, Forced Aeration Composting & Biodrying System IPS Composting & Biodrying Page 18 Date Author filename.ppt Water Technologies

19 IPS System Overview Thermocouples, Aeration & Water System Thermocouple Aeration IPS Composting & Biodrying Page 19 Date Author filename.ppt Water Technologies

20 IPS System Overview IPS Biodrying & Composting Process Animation IPS Composting & Biodrying Page 20 Date Author filename.ppt Water Technologies

21 IPS System Overview Page 21 Date Author filename.ppt Water Technologies

22 Facility Description Facility Age: No. Bays: Materials Processed: Bristol 15 years 4 Primary/Secondary sludge with shredded green waste Merrimack 15 years 15 Undigested/Digested sludge & septage w/ sawdust, shredded green waste Sludge ds: Agitator Power: Ambient Temp.: Bay Dimensions: Blower Qty./Power: Distance/Agitation: Avg. 25% 30 HP (recent replacement) 59 F to 100 F 12 feet 10 25% 25 HP (original) 8 F to 54 F 220 ft long x 6 ft wide x 6 ft deep 5/3 HP Facility Data Page 22 Date Author filename.ppt Water Technologies

Achieving PFRP was primary objective 22% ds sludge blended with Recycle (85% ds) Optimize a & a to achieve PFRP (3 days @ 55 C)

23 Bristol Pilot Study Bristol Study Phase I: Drying was primary objective Drying as quickly as possible 22% ds sludge blended with dried biosolids pellets (>90%ds) Optimize agitation & aeration (a & a) to achieve 65% ds finished product Phase II: Achieving PFRP was primary objective 22% ds sludge blended with Recycle (85% ds) Optimize a & a to achieve PFRP (3 55 C) & VAR (14 45C) Achieve a >65% solids finished product (secondary) ` Strategies Page 23 Date Author filename.ppt Water Technologies

Merrimack Study Merrimack Study Pre-Pilot Test: Generate dried biosolids for Pilot Test 4 Passes run to create a carbon-free amendment for Pilot

@ 19% DS blended with sawdust @ 85%ds Optimize a & a to achieve 65% ds finished product Pilot Test: Achieve 65% ds dried biosolids from 45% ds

24 Merrimack Study Merrimack Study Pre-Pilot Test: Generate dried biosolids for Pilot Test 4 Passes run to create a carbon-free amendment for Pilot Test Sludge 19% DS blended with 85%ds Optimize a & a to achieve 65% ds finished product Pilot Test: Achieve 65% ds dried biosolids from 45% ds Test Mix 4 Passes run to test variables (agitation frequency/mix variation/aeration) Optimize a & a to dry and achieve PFRP Temps. Sludge solids declined due to seasonal variations Mimic effect of longer bay length Strategies Page 24 Date Author filename.ppt Water Technologies

25 Mechanically Enhanced Biodrying RESULTS. Bristol Study Phase I: Reached 65% ds after Day 9 & 88% ds after Day 24 Phase II: Achieved PFRP Temperatures, dried from 41% ds to 68% ds in 18 days Results Page 25 Date Author filename.ppt Water Technologies

26 Mechanically Enhanced Biodrying. RESULTS Merrimack Study Pre Pilot Test: Created carbon-free recycle for PT Reached 65% ds after Day 24 Pilot Test: Low solids content of sludge had a negative cascading effect on the ability to achieve the desired Test Mix and Recycle solids content Challenging results from trial defined the parameters required to achieve 65% solids content: Results Page 26 Date Author filename.ppt Water Technologies

27 Mechanically Enhanced Biodrying RESULTS. BOUNDARY CONDITIONS FOR BIOSOLIDS TO ACHIEVE BIODRYING Sludge 20% DS, 60% VS Input Mix 45% DS Results Page 27 Date Author filename.ppt Water Technologies

28 Merrimack Pilot Study Summary of MEB Output Test Passes Passes P4, 1, 2, 3 and 4 Duration Pass P4 thru 4: 3 Nov 26 Feb (85 days) Average sludge dry solids: 20% to 16% Average recycle dry solids: 52% to 45% Average input mix dry solids: 42% to 37% Average output dry solids: 55% to 47% Ambient Temperature: 8 F to 54 F Page 28 Date Author filename.ppt Water Technologies

29 Solids Content vs Biodrying Time (Bristol) 90 Relationship between composting time and percent dry solids Bristol, RI - Pellet amendment study Phase 1 Composting material, DS, % DS, % DS, % y = x R^2 = 0.85 days 1-7 Phase 1: June 23 through July 19, 2008 Bristol Department of Public Works/Siemens Water Technologies Corp. y = x x^2 R^2 = 0.94 days Biodrying time, days Page 29 Date Author filename.ppt Water Technologies

30 Solids/Energy Content vs Drying Ability Solids Content vs Drying Ability % Solids Content Sludge %ds 17.2 %ds 16.8 %ds 15.7 %ds 1 2 Time (Day 1 - Day 21) Solids Content of Sludge & Recycle vs Drying Ability Solids Retention Charge Sludge Recycle Infeed Discharge Increase Time Date (% ds) (% ds) (% ds) (% ds) (% pts) (days) 21-Dec Dec Jan Page 30 Date Author filename.ppt Water Technologies

31 Temperature vs. Time (Bristol) Compost temperature - Bristol, RI, Phase 2. July 2008 Screened compost used as amendment with dewatered biosolids Compost temperature, C Charge 1 Charge 2 Charge 3 T C average PFRP 55 C VAR min 40 C Composting time, days Page 31 Date Author filename.ppt Water Technologies

32 Bay Volume Reduction Volume reduction in the bay 20% Bristol Volume Reduction Merrimack Volume Reduction Page 32 Date Author filename.ppt Water Technologies

33 Temperature vs. Time (Merrimack) Temperature vs. Biodrying Time Merrimack, NH Study, Pass 4 - December 2009 Sludge with Dried Biosolids Recycle 70 Temperature, C 60 PFRP, 55 C Temperature, C VAR minimum, 40 C Biodrying Time, days Page 33 Date Author filename.ppt Water Technologies

34 Temperature Vs Time with Agitation 70 Compost temperature - Bristol, RI, Charge 4. June/Jul 2008 Heat dried pellets used as amendment with dewatered biosolids. 60 T C Charge 4 Temperature C Biodrying Time, days Page 34 Date Author filename.ppt Water Technologies

35 Pilot Study Variables Uncontrollable Variables: Sludge Solids Content ( 20% required) Physical/Chemical Properties of the Sludge In Bay Volume Reduction (affects recycle quantity) Charge Densities/Stickiness (affects process ability and capacity) Ambient Air Temperature and Humidity Page 35 Date Author filename.ppt Water Technologies

36 Pilot Study Variables Controllable Variables: Recycle (minimum 65% solids) Bay charge size (maximize for heat retention & recycle quantity) Test mix composition (45% min & biodegradable VS) Aeration rates and scheme (optimize for drying first, then PFRP ) Agitator frequency (once daily) Ventilation rates (min. to remove moisture from building 8 ACPH) Page 36 Date Author filename.ppt Water Technologies

(m2) (KW/m2) 25 18.5 3.7 5.0 30 22.5 3.7 6.1 50 37.5 4.6 8.1 100 74.5 7.

37 Energy Consumption 15 year old 25 HP Agitator Agitator Power to Area Ratio Summary Agitator Area Cross Power:Area Motor Power Secion Ratio (HP) (KW) (m2) (KW/m2) New 100 HP Agitator Page 37 Date Author filename.ppt Water Technologies

38 Energy Consumption Energy Consumption per Unit of Test Mix Power Consumption per Power Consumption per Volume of Test Mix Weight of Test Mix Bristol - Fuel 0.4 liters/m3 0.8 liters/tonne Bristol - Electricity Phase I 1.8 KWH/m3 3.4 KWH/tonne Bristol - Electricity Phase II 2.9 KWH/m3 5.9 KWH/tonne Merrimack - Electricity 8 KWH/m3 15 KWH/tonne Assumes average density of test mix at 0.53 tonnes/m 3 Merrimack agitator used 1 hour per day, assumed full draw traveling the length of the bay blowers ran 3 hours/day Page 38 Date Author filename.ppt Water Technologies

39 Heat Value Calculation Estimated Heat Value of Biodried Biosolids Using Haug's equation for compost, for this application only the Volatile Solids (VS) have energy Volatile Heat Value Dry Solids Adjusted Solids Dry Dry Solids Moisture Heat Value % of VS Bulk Solids Content Content for Moisture Dry Solids (kj/kg) (kj/kg) (%) (%) (kj/kg) (kcal/kg) Notes Wet Wood - 19, ,300 2,910 Typical Compost 87 23,260 20, ,060 3,090 Merrimack MEB Output 62 23,260 14, ,780 2,080 (Lowest Average Recorded) Expected MEB Output 62 23,260 14, ,150 2,400 (20% Sludge/45% Test Mix) Bristol MEB Output 79 23,260 18, ,290 3,140 (Pass II/Charge II) Estimated MEB AVG 60 23,260 13, ,820 2,320 (Based on China samples) kcal/kg kcal/kg 5,500 3,301 Sources: d Equation from Textbook of Wood Technology -Panshin, A.J. and C. dezeeuw e 23,260 kj/kg (10,000 BTU/lb) from The Practical Handbook of Compost Engineering -Haug, Roger, 1993 Page 39 Date Author filename.ppt Water Technologies

40 Mechanically Enhanced Biodrying (MEB) Mechanically Enhanced Biodrying relies on biological & mechanical processes Biodried biosolids can be used successfully as amendment Key process boundary conditions to achieve 60% DS in product: Sludge 20% ds at 60% VS and Infeed Mixture at 45% ds IPS MEB process effectiveness declines with solids contents lower than above. Conclusions Page 40 Date Author filename.ppt Water Technologies

41 Mechanically Enhanced Biodrying (MEB) Sludge characteristics determine time requirements to biodry and meet PFRP. 20 days will achieve a typical 20 percentage point increase in dry solids IPS equipment performed well and not impacted by higher density materials. Bay volume reduction of about 20% (sufficient volume to meet process needs and provide surplus for fuel/fertilizer) Sufficient time & energy available in MEB process to achieve pathogen destruction if parameters are met Conclusions Page 41 Date Author filename.ppt Water Technologies

42 Mechanically Enhanced Biodrying (MEB) Low temperatures should not impede process if parameters are met Higher Heat Value of finished product estimated at 8,500 kj/kg 50% wet wood High percentage of output used as amendment will result in reduced end product transportation cost Conclusions Page 42 Date Author filename.ppt Water Technologies

43 Acknowledgements Thank You! We also gratefully acknowledge the administrators and staff at the Anthony Dupont Composting Facility in Bristol, Rhode Island USA and at the Merrimack, New Hampshire USA Composting Facility. Page 43 Date Author filename.ppt Water Technologies

44 Contact Information Lissa Ham Technical Sales Manager IPS Composting Systems Siemens Industry Inc. Water Technologies Business Unit 55 Technology Drive Suite 201 Lowell, MA Mobile: Telephone: Fax: : Website: lissa.ham@siemens.com Page 44 Date Author filename.ppt Water Technologies

COMPOSTING FOOD PROCESSING WASTES

COMPOSTING FOOD PROCESSING WASTES GEOFFREY A. KUTER, PH.D. AND LEWIS M. NAYLOR, PH.D. INTERNATIONAL PROCESS SYSTEMS, INC. LEBANON, CONNECTICUT 06249 ABSTRACT Beginning in the early 1970's, composting has